An investigation into the effectiveness of mechanical dredging to remove Corbicula fluminea (Müller, 1774) from test plots in an Irish river system

Published source details Sheehan R., Caffrey J.M., Millane M., McLoone P., Moran H. & Lucy F (2014) An investigation into the effectiveness of mechanical dredging to remove Corbicula fluminea (Müller, 1774) from test plots in an Irish river system. Management of Biological Invasions, 5, 407-418.
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This study is summarised as evidence for the following.

	Action	Category
	Asian clams: Mechanical removal Action Link

Asian clams: Mechanical removal

A replicated, controlled, before-and-after field trial conducted during 2012 in the tidal reaches of the River Barrow, Ireland (Sheehan et al. 2014) found that dredging could reduce the biomass and density of the Asian clam Corbicula fluminea. At a site with high clam biomass and high clam density, dredging achieved a reduction of greater than 95% biomass and 95% clam density. At a site with a low density and low biomass of clams dredging achieved a reduction of biomass by 82% and density by 65%. At a site with high density and low biomass of clams dredging achieved a reduction of biomass by 74% and density by 92%. There was no difference in the effectiveness of the three dredge types used. In each of the three sites, three control and three experimental plots were marked by buoys. In each plot, clam biomass and density was estimated before and after trials using five 0.25m² quadrats which were hand-searched by divers. The three experimental plots at each site were dredged using eithera box dredge, an electric dredge or a hydraulic dredge. Dredging selectively removed larger clams (18-32 mm length).